Injection-molded vacuum packaging machine

ABSTRACT

A vacuum packaging machine having a chamber comprised of an injection-molded lid and an injection-molded basin.

FIELD OF THE INVENTION

[0001] This invention relates to a vacuum packaging machine having aninjection-molded lid and basin comprised of an impact-modified resin.

BACKGROUND OF THE INVENTION

[0002] Vacuum packaging is the process of removing air from around aproduct and then sealing that product in an airtight environment. Vacuumpackaging machines have a wide variety of food and non-foodapplications. A vacuum packaging machine may protect food fromcontamination from the air, the most common cause of spoilage. Themachine may also be used for storing medical applications or electroniccomponents.

[0003] Various vacuum packaging machines are well-known in the art. Theyvary in size from small table-top machines to large free-standingmachines. For example, Applicant manufactures a series of table-topvacuum packaging machines marketed under the name ULTRAVAC®, thefeatures of which are incorporated herein by reference. In general, themachines are comprised of a vacuum chamber made of a basin and a lid.After opening the lid, the product to be vacuum-sealed is inserted intothe chamber in a plastic pouch and laid across a seal bar. Once the lidis closed, a pump creates a vacuum inside the chamber and pouch toremove all of the atmosphere inside. The product is then hermeticallysealed by heat and pressure from the seal bars. Some vacuum packagingmachines contain a glass window in the lid to enable the user to viewthe contents of the chamber.

[0004] All vacuum chambers, including those utilized in Applicant'sULTRAVAC® machines, are subject to significant stresses during use. As aresult, such vacuum chambers should be designed to withstand a vacuumpressure of 5 torr. Moreover, the chamber should be preferably built towithstand approximately 100,000 cycles annually.

[0005] Four designs of vacuum chambers are known in the art. Some vacuumpackaging machines utilize a stainless steel chamber. The chamber ismade from heavy gauge sheet material with structural members to create achamber using break and weld construction. This process has both highmaterial and labor costs.

[0006] Another vacuum packaging chamber is made from aluminum castingsdesigned with appropriate structures to withstand the load. While thisprocess has lower material and labor costs, it does require subsequentmachining and has high tooling costs. In addition, aluminum castings arenot inherently hygienic.

[0007] Other machines use heavy acrylic sheet material (typically 0.75to 1.0 inch) that is pressed into a bowl shape and then machined to thefinal dimensions. This process requires long cycle times in the press,significant machining costs, and high material costs.

[0008] Finally, smaller chamber lids comprised of a thermoset materialhave been prepared using compression molding, although no chamber basinshave been prepared using compression molding. The process limits thefeatures that can be molded into a single part. After molding, the lidusually requires subsequent machining and the parts are susceptible tocreep under heat exposure. Thus, there still remains a need in theindustry of a vacuum packaging chamber that is comprised of ahigh-strength material and that can be manufactured at low costs.

SUMMARY OF THE INVENTION

[0009] Accordingly, the present invention provides a vacuum packagingmachine having an injection-molded lid and an injection-molded basincomprised of a high-strength material that can be manufactured at a lowcost. During operation, the chamber can withstand vacuum of 5 torr.Moreover, the invention can withstand 100,000 cycles of use annually.The machine further has negligible or no shrink rate so that the chamberdoes not warp. Finally, the machine is not susceptible to creep uponexposure to heat.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A more complete appreciation of the invention and many of theadvantages thereof will be readily obtained as the invention becomesbetter understood by reference to the detailed description whenconsidered in connection with the accompanying drawings, wherein:

[0011]FIG. 1 is an illustration of the injection-molded vacuum packagingmachine having an injection-molded lid and basin wherein the lid is inthe open position.

[0012]FIG. 2 is a side view of the vacuum packaging machine of thepresent invention with the side of the skirt removed to show theinterior components of the machine.

[0013]FIG. 3 is a perspective view of the lid and a hinge block removedfrom the machine.

[0014]FIG. 4 is a top view of the lid of the vacuum packaging machine.

[0015]FIG. 5 is a bottom view of the lid of the vacuum packagingmachine.

[0016]FIG. 6 is a two-dimensional cross-section of the vacuum packagingmachine taken through line 6 ¹-6 ¹ in FIG. 4.

[0017]FIG. 7 is a two-dimensional cross-section of the lid of the vacuumpackaging machine taken through line 7 ¹-7 ¹ in FIG. 5.

[0018]FIG. 8 is an expanded perspective view of the basin, seal bar, andseal bladder of the vacuum packaging machine.

[0019]FIG. 9 is a top view of the basin of the vacuum packaging machine.

[0020]FIG. 10 is a bottom view of the basin of the vacuum packagingmachine.

[0021]FIG. 11 shows a front view of the basin of the vacuum packagingmachine.

[0022]FIG. 12 is a back view of the basin of the vacuum packagingmachine.

[0023]FIG. 13 is a side view of the basin of the vacuum packagingmachine.

[0024]FIG. 14 is a two-dimensional cross-section of the basin takenthrough line 14 ¹-14 ¹ in FIG. 10.

[0025]FIG. 15 is a two-dimensional cross-section of the basin takenthrough lines 15 ¹-15 ¹ in FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0026] As best illustrated by FIG. 1, the present invention relates to avacuum packaging machine 10, and in particular to the chamber 20 of thevacuum packaging machine 10, which is comprised of an injected moldedlid 30 and basin 25. While the chamber 20 of the present invention couldbe designed for vacuum packaging machines of various types and sizes,the preferred embodiment of the present invention is a chamber designfor a table top type vacuum packaging machine 10, as illustrated in FIG.1.

[0027]FIG. 1 illustrates the table top vacuum packaging machine with thelid 10 in the “open position” to allow an operator to load the machine10 with product (not shown) to be vacuum sealed. In contrast, FIG. 2illustrates the vacuum packaging machine 10 in the closed position. Asseen in FIGS. 1 and 2, the vacuum chamber 20 sits on and within arectangular skirt 14, which houses the interior components of the vacuumpackaging machine 10, such as the vacuum pump 15, the hinge block 18 andlid spring 19, which fastens the chamber lid 30 to the basin 25, and thecontrol panel 16.

[0028] As previously discussed, the product (not shown) to bevacuum-sealed is inserted into the chamber 20 in a plastic pouch (notshown) and laid across a seal bar 11. Once the lid 30 is closed, a pumpcreates a vacuum inside the chamber 20 and pouch to remove nearly all ofthe inside. The product is then hermetically sealed by heat and pressurefrom the seal bars 11. Because of the vacuum being pulled through thechamber 20, the lid 30 and basin 25 of the chamber 20 of the vacuummachine 10 must be designed to withstand a vacuum pressure of at least 5torr and built to withstand approximately 100,000 cycles annually.

[0029] To achieve this desired strength and endurance, both the basin2-5 and lid 30 of the chamber 20 of the present invention are preferablymolded from IOSPLAST® 101-LGF-40 (Dow Chemical Company) or CelstranTPU-GF30-01 (Ticona, Wynona, Minn.), but may be made of any typicalinjection molding material capable of withstanding high vacuumpressures. The injection-molding machine (not shown) used to create thelid 30 and chamber 25 preferably has a tonnage of 1000 and a barrel sizeof 225 oz. Processing cycle times range from about 152 to 162 secondswith a standard injection time of about 4.5 seconds, injection hold timeof about 4.0 seconds, and a cooling time of about 120.0 seconds. Nozzletemperatures range in the area of about 460° F. Injection moldingpressures are in the range of 1400 to 1500 psi, with a hold pressure of500 and a back pressure of 10 psi. The shot size is 14.91 lbs. for thebasin and 9.33 lbs. for the lid. The dryer temperature is about 180° Fwith an approximate drying time of 4 hours.

[0030] A. The Injection-Molded Lid

[0031] The chamber lid 30 of the present invention is best illustratedin FIGS. 1 and 3-7. The lid 30 is generally rectangular and concave inshape and, in the preferred embodiment, measures 563.0 mm by 474.0 mmand has a depth of 97.5 mm. Although the lid 30 comprises a continuouspiece of material made from an injection molding process, the lid 30 hasa number of functional attributes that shall be separately described.Moreover, although the embodiment of the lid described herein relates toone for a table-top vacuum-packaging machine, one skilled in art willrecognize that various attributes may be modified, removed, or addedwhen used in connection with different vacuum packaging machines.

[0032] As shown in FIGS. 4 and 5, the lid 30 is comprised of a toprectangular piece 35 having a rectangular hole 40 and four trapezoidalside pieces 60, 70, 80, 90 extending from the top rectangular piece 35.The non-parallel edges of two adjacent trapezoidal side pieces cometogether to form a rounded corner of the lid (see FIGS. 1 and 3-5). Thelid thus contains four rounded corner areas 150, 160, 170, 180 definedby the edges of the trapezoidal side pieces. Overall, the lid 30 has aconcave shape.

[0033] The top rectangular piece 35 has both an outer surface 37 and aninner surface 39. A rectangular L-shaped ledge 57 extends from the innersurface 39 into the hole 40. The L-shaped ledge 57 supports arectangular piece of glass (not shown) for viewing the contents of thechamber 20. In the preferred embodiment, the rectangular hole measures241.3 mm by 165.1 mm, and the ledge extends into the hole 12.7 mm.

[0034] In the preferred embodiment, each of the four side pieces 60, 70,80 and 90 contains two sections: an upper section (62, 72, 82, 92) and alower section (64, 74, 84, 94). The lower section is positioned morevertically (relative to the top rectangular piece 35) than the uppersection in order to give the lid 30 a more concave shape overall (seeFIGS. 1 and 3). The area where the top rectangular piece 35 meets eachupper section is rounded, having a radius of 25.4 mm in the preferredembodiment. Similarly, the area where the each upper section meets eachcorresponding lower section is also rounded, having a radius of 22.2 mm.The upper section and lower section may have a different thickness. Inthe preferred embodiment, the upper section (62, 72, 82, 92) has athickness of 7.0 mm while the lower section (64, 74, 84, 94) has athickness of 6.4 mm.

[0035] Each of the four trapezoidal side pieces 60, 70, 80, 90 furthercontains two faces: an outer face (66, 76, 86, 96) and an inner face(68, 78, 88, 98). The lower section (64, 74, 84, 94) of each side piecealso contains a rounded bulging edge 50 with a groove 52. Atwo-dimensional cross-section of the rounded bulging edge 50 and thegroove 52 is depicted in FIG. 6. In the preferred embodiment, the groove52 has a width of 8.0 mm and a depth of 5.8 mm. The exterior edges 53and the interior edges 55 of the groove 52 are rounded, having a radiusof 1.2 mm and 2.4 mm, respectively. As shown in FIG. 3, the lid gasket17 fits into the groove 52.

[0036] Trapezoidal side piece 60 further contains an L-shaped handle 100extending from the lower section 64. The handle 100 has a preferablethickness of 6.35 mm. A cross-section of the handle 100 is shown in FIG.6.

[0037] Trapezoidal side piece 80 contains two hinge extensions 105located in outer face 86 of the lower section 84. In the preferredembodiment, the lid 30 is connected to the basin 25 using the hingeassembly described in Harte, U.S. Pat. No. 5,465,557, assigned to KochSupplies Inc., which is fully incorporated here by reference. The hingeextensions 105, which contain one or more screw holes 107, are used toconnect the injection molded lid 30 to two hinge blocks 18 (see FIG. 1).A two-dimensional cross-section of one of the hinge extensions is shownin FIG. 7. Various other hinge assemblies, however, may be used to mountthe lid 30 to the basin 25.

[0038] As shown in FIG. 5, the lid 30 may contain one or morereinforcement bars 120. In the preferred embodiment, four reinforcementbars span part of the ledge 57, the inner surface 39 of the toprectangular piece 35, and the inner faces 68, 78, 88, 98 of the fourtrapezoidal side pieces 60, 70, 80, 90. The reinforcement bars 120 arepositioned to form a grid in the shape of a “tic-tac-toe” square, eachbar being parallel to one other bar and perpendicular to two other bars.The bars 120 are positioned so that the “center square” formed by thebars outlines part of the L-shaped ledge 57 in the lid 30. The bars havepreferred thickness of 5.1 mm and a height of 29.4 mm.

[0039] The four rounded corners 150, 160, 170, 180 each contain featuresdesigned for additional strength. First, the thickness of the lid at thecorners is gradually increased. In the preferred embodiment, thethickness of the corners is increased by 3.2 mm at the corners. Second,as shown in FIG. 5, the corners 150, 160, 170, 180 may contain one ormore reinforcement strips 190. The reinforcement strips 190 preferablyextend from the reinforcement bars 120 to the rounded bulging edge 50located near the hinge extensions 105. These reinforcement strips 190thus provide the lid 30 with additional strength near the hingeextensions 105.

[0040] The inner faces 68, 78, 88, 98 of the upper sections 62, 72, 82,92 of each trapezoidal side piece also contain an attachment boss 194.Two of the attachment bosses 194 are used to mount the back-up bar 12 tothe lid 30 while the other two provide additional strength to the lid30.

[0041] As illustrated by FIG. 3, the lid-gasket 17 and a hinge block 18are attached to the basin and used to anchor the lid 30 to the basin 25.

B. The Injection-Molded Basin

[0042] The basin 25 of the chamber 20 is best illustrated in FIGS. 1 and8-15. FIG. 8 shows an expanded perspective view of the injection moldedbasin 25 with a seal bar 11 and seal bladder 13. Although the basin 25comprises a continuous piece of material made from an injection moldingprocess, the basin 25 has a number of functional attributes that shallbe describe separately. Although the embodiment for the basin describedherein relates to one for a table-top vacuum-packaging machine, oneskilled in the art will recognize that the various attributes may bemodified, removed, or added when used in conjunction with a differentvacuum packaging machine.

[0043] The basin 25 is comprised of a bottom wall 210 having an interiorsurface 215 and exterior surface 217 and four side walls 220, 230, 240,and 250, each having an interior face (222, 232, 242, 252) and anexterior face (224, 234, 244, 254). In the preferred embodiment, thebottom wall measures 495.0 mm×422.0 mm×6.4 mm and is slightly concave,having a depth of 3.8 mm. The side walls have a thickness of 6.5 mm.

[0044] The four side walls 220, 230, 240, 250 are connected to eachother so as to form a rounded corner having a radius of 6.4 mm (see FIG.8). Similarly, the four side walls are connected to the bottom wall 210to form a rounded connection having a radius of 6.4 mm (see FIG. 8).

[0045] Extending from three of the side walls 220, 230, 240 is anL-shaped lip 260 shown in FIGS. 14 and 15. The lip 260 has a horizontalportion 262 measuring 40.2 mm and a vertical portion 264 measuring 25.0mm. The vertical portion 264 has a 14.2 mm thickness. The verticalportion 264 contains a vertical slit 266. During operation, the skirt 14fits into the slit 266 and connects the skirt 14 to the basin 25.

[0046] A flattened edge 270 extends horizontally from side wall 250. Inthe preferred embodiment, the flattened edge 270 has a width of 95.2 mm.Thus, in the preferred embodiment, the basin has a total length of 633.7mm (measured as a 495.0 mm bottom piece and a 92.2 mm flattened edge).The edge 270 contains two hinge slots 275. The two hinge slots 275receive the two hinge blocks 18 used to fasten the lid 30 to the basin25. As shown in FIG. 10, the flattened edge 270 also contains fourstrength strips 218 in each corner. Each strength strip 218 contains aslot 219.

[0047] The basin 25 may contain one or more strength ribs. In thepreferred embodiment, seven u-shaped strength ribs 280 span the exteriorsurface 217 and exterior faces 224 and 234 along the length of the basin25. Each corner of the “U” has a radius of 24.4 mm (see FIG. 8). Thethickness of the strength ribs is 3.79 mm along the exterior surface 217and is thinner along exterior faces 224 and 234.

[0048] Four u-shaped strength ribs 290 span the exterior surface 217 andexterior faces 244 and 254 along the width of the basin 25. Each cornerof the “U” has a radius of 24.4 mm (see FIG. 8). Part of two of thefour-u-shaped strength ribs 291 are positioned on exterior faces 254adjacent to each hinge slot 275 and contain one or more pivot holes 277.Two hinge plates 279 also having pivot holes 277 extend from exteriorfaces 254 adjacent to each hinge slot 275. During use, the ribs 291 andthe hinge plates 279 are used to fasten a hinge block 18 to the basin25. A fifth L-shaped strength rib 293 spans the exterior surface 217 andthe exterior face 244 (but not exterior 254). Strength rib 293 does notspan the exterior face 254 so that a vacuum block assembly 255 (seeFIG. 1) may be attached in that region of the basin 25. FIG. 12 shows avacuum hole 256 for receiving a vacuum hose (not shown) and two vacuumblock screw holes 257 used to mount the vacuum block assembly 255.

[0049] The strength ribs 290, 293 spanning the length of the basin 25and the strength ribs 280 spanning the width of the basin 25 togetherform a grid along the exterior surface 217 of the bottom wall 210 of thebasin 25. In the preferred embodiment, the strength ribs have athickness ranging from 2.5 to 7.0 mm. In addition, the strength ribs aregenerally wider along the exterior surface 217 as compared to theexterior faces 224, 234, 244, 254. In the preferred embodiment, thestrength ribs have a width of 25.5 mm along the exterior faces 224, 234,244, 254 and a width of 41.3 mm along the exterior surface 217.

[0050] The bottom wall 210 contains several features useful in thefunction of the packaging machine 10. As shown in FIGS. 9, 10, and 15,near side wall 240, the bottom wall 210 has a seal barb 300. In thepreferred embodiment, the bladder barb 300 has an outer radius of 30.0mm and an inner radius of 19.9 mm. Turning now to FIGS. 9 and 15, thebottom wall 210 also contains two vertical pins 305 that operate as aguide for the seal bar 11. In the preferred embodiment, the verticalpins 305 have a height of 20.8 mm and a radius of 12.6 mm. FIGS. 9 and15 further show that extending from the bottom wall 210 along theinterior faces 222, 232 of side walls 220, 230 are two vertical bars 310that operate as a guide for the filler plates in the machine. FIG. 10illustrates that the basin 25 contains two spring bosses 315. A springextends between each hinge block 18 and the spring bosses 315 as shownin FIG. 2. Six holes 320 are located along strength bars 280 to permitattachment of wires and vacuum hoses (not shown) needed to operate themachine. Two apertures 325 are located in the bottom wall 210 to permitattachment of wires for the seal bar. Finally, strength bars 280, 290,and 293 contain a number of cylindrical ejector pin bosses (not depictedin the drawings). In the preferred embodiment, there are approximately26 ejector pin bosses located on strength bars 280 and 290 along theexterior surface 217 of the basin.

[0051] Although the foregoing detailed description of the presentinvention has been described by reference to a single exemplaryembodiment, and the best mode contemplated for carrying out the presentinvention has been herein shown and described, it will be understoodthat modifications or variations in the structure and arrangement ofthis embodiment other than those specifically set forth herein may beachieved by those skilled in the art and that such modifications are tobe considered as being within the overall scope of the presentinvention. Therefore, it is contemplated to cover the present inventionand any and all modifications, variations, or equivalents that fallwithin the true spirit and scope of the underlying principles disclosedand claimed herein. Consequently, the scope of the present invention isintended to be limited only by the attached claims.

We claim:
 1. A vacuum packaging machine having a vacuum pump and avacuum chamber, wherein said chamber is comprised of a lid and a basin,said lid being injection-molded.
 2. The machine as recited in claim 1wherein said lid is comprised of a glass-filled resin.
 3. The machine asrecited in claim 1 wherein said lid is comprised of ISOPLAST 101 orCelstran TPU-GF30-01.
 4. The machine as recited in claim 1 wherein saidlid is concave.
 5. The machine as recited in claim 1 wherein said lidcontains a hole for viewing the contents of said machine duringoperation.
 6. The machine as recited in claim 5 further comprising anL-shaped ledge that extends into said hole.
 7. The machine as recited inclaim 1 wherein said lid has four trapezoidal side pieces.
 8. Themachine as recited in claim 7 wherein said trapezoidal side piecescontain both an upper section and a lower section, said upper sectionbeing positioned more vertically than said lower section.
 9. The machineas recited in claim 1 wherein said lid contains an edge having a groove.10. The machine as recited in claim 1 wherein said lid contains at leastone hinge extension.
 11. The machine as recited in claim 1 wherein saidlid contains at least one reinforcement bar.
 12. The machine as recitedin claim 11 where in said lid has two parallel and two perpendicularreinforcement bars.
 13. The machine as recited in claim 1 wherein saidlid contains at least one thickened corner having a reinforcement strip.14. A vacuum packaging machine having a vacuum pump and a vacuumchamber, wherein said chamber is comprised of a lid and a basin, saidbasin being injection-molded.
 15. The machine as recited in claim 14wherein said basin is comprised of a glass-filled resin.
 16. The machineas recited in claim 14 wherein said basin is comprised of ISOPLAST 101or Celstran TPU-GF30-01.
 17. The machine in claim 14 wherein said basinhas an L-shaped lip.
 18. The machine in claim 17 wherein said L-shapedlip contains a strength strip in at least one corner of said L-shapedlip.
 19. The machine in claim 14 wherein said basin has at least aflattened edge containing at least one hinge slot.
 20. The machine inclaim 14 wherein said basin contains at least one strength rib.
 21. Themachine in claim 20 wherein said at least one strength rib contains atleast one pivot hole, said pivot hole used to mount a hinge blockassembly to said lid.
 22. The machine in claim 20 wherein said basin hasa bottom wall having both an interior surface and an exterior surfaceand at least one strength rib contains at least one hole useful forpermitting wires to cross the exterior and interior surface.
 23. Themachine in claim 16 wherein said basin contains two vertical pins, saidpins useful for guiding a seal bar during operation.
 24. The machine inclaim 16 wherein said basin contains two vertical bars, said bars usefulfor guiding at least one filler plate during operation.
 25. A vacuumpackaging machine having a vacuum chamber, wherein said chamber iscomprised of an injection-molded lid and an injection-molded basin. 26.The machine as recited in claim 25 wherein said injection molding uses aglass-filled resin.
 27. The machine as recited in claim 25 wherein saidinjection molding uses ISOPLAST 101 or Celstran TPU-GF30-01.